Various systems and methods are currently known for computerized detection of abnormalities in radiographic images, such as those disclosed by Giger et al. in RadioGraphics, May 1993, pp. 647–656; Giger et al. in Proceedings of SPIE, Vol. 1445 (1991), pp. 101–103; U.S. Pat. No. 4,907,156 to Doi et al.; U.S. Pat. No. 5,133,020 to Giger et al.; U.S. Pat. No. 5,343,390 to Doi et al.; U.S. Pat. No. 5,491,627 to Zhang et al. These systems are generally referred to as Computer-Aided Diagnosis systems, Computer-Aided Detection systems, or simply, CAD systems. Such systems are believed to be particularly useful to radiologists and other medical specialists in diagnostic processes and specifically in radiological screening procedures.
In a radiological screening procedure, such as screening mammography, true abnormalities such as cancers are believed to occur at a typical rate of about one case per one hundred patient examinations. It is believed a CAD system, serving as an electronic reminder or second reader, can assist radiologists in obtaining higher detection rates, or higher sensitivity for abnormalities. Additionally, such CAD systems can assist radiologists in reducing the misdiagnosis rate, or lowering the false negative rate. Thus, it is believed that the use of such CAD systems will continue to increase.
Since such CAD systems typically operate on medical images in high-resolution digital format, film-based medical images ordinarily must be scanned by a high-resolution scanner to convert the image data into digital form. As systems change, the digital image acquisition devices cannot be interfaced with such CAD systems. Additionally, in a practice covering multiple areas, for example mammograms as well as CT scans, multiple such analysis devices must be used, one for each modality. This is wasteful, and reduces the use of such CAD systems.